High sensitivity troponin T in acute medicine; more questions than answers?

Troponin testing in acute medicine is routine. The introduction of a high sensitivity assay (hs Tn T) has created uncertainty regarding the clinical significance of 'abnormal' troponin T levels. The previous assay could not detect troponin levels <30 ng/l.

To characterize those with a hs Tn T ≥14 ng/l. Prospective cohort study of consecutive admissions to an acute medical unit.

Troponin was measured in 564 consecutive patients (∼50% of all admissions) over 1 month; was ≥14 ng/l in 224 (40%) of which 220 patients had demographic data for this analysis. Median (inter-quartile range) peak troponin was 47.5 ng/l (24-130) and 36% had a Tn T between 14 and 30 ng/l. Mean [standard deviation (SD)] age was 72 (12) years and 57% were male. Only 44 patients (20%) had an acute myocardial infarction, reflecting the increased sensitivity but reduced specificity of the assay. Prognosis was poor with 31% mortality at 1 year. Over a mean (SD) follow-up of 648 (61) days, there were 87 deaths (40%). Those with a primary non-cardiac diagnosis (n = 126) had poorer survival than those with a primary cardiac diagnosis (n = 94). Troponin elevation related to sepsis conferred a very poor prognosis with 24 deaths (70%) over the follow-up period.

Elevated hs Tn T is very common in acute medicine, but myocardial infarction as an explanation is uncommon. Overall, the prognosis is poor with a tendency to worse outcomes in those with a primary 'non-cardiac' diagnosis.